1. Field of the Invention
This invention relates to a vacuum cleaner structure and in particular to means for adjustably raising the front portion of the vacuum cleaner nozzle so as to regulate the height of the nozzle opening and the rotatable cleaning brush customarily located therein relative to the surface being cleaned such as for use with different pile height carpets or for bare floors.
2. Description of the Prior Art
U.S. Pat. No. 1,850,710 discloses an adjustment mechanism for a vacuum cleaner comprising a rotatable knob fixed to a cam for vertically adjusting the nozzle height.
U.S. Pat. No. 2,104,453 discloses a vacuum cleaner having wheel height adjustment means in which supporting wheels are swung on a pivot to adjust the nozzle relative to the surface.
U.S. Pat. No. 2,712,669 discloses an adjustment knob for a vacuum cleaner nozzle height adjustment which has an index portion and a serrated edge.
U.S. Pat. No. 2,734,217 discloses a height adjuster for a vacuum cleaner nozzle using a cam with grooves and calibration markings.
U.S. Pat. No. 2,741,488 discloses a vacuum cleaner with a cam of varying radius rotated by actuation of a foot pedal to adjust the height of the nozzle relative to the surface.
U.S. Pat. No. 3,683,448 discloses a vacuum cleaner height adjusting cam which is rotated by a serrated knob to pivotally move a supporting axle.
Other U.S. patents showing various adjustable supporting mechanisms are U.S. Pat. Nos. 1,348,585; 1,482,953; 1,733,384; 3,148,400 and 4,167,801.
U.S. patent application Ser. No. 357,135, entitled "Vacuum Cleaner Nozzle Lift Device", filed Mar. 11, 1982, by David G. Koland now U.S. Pat. No. 4,437,205, issued Mar. 20, 1984, and, assigned to the same assignee as the present invention, discloses a foot pedal actuated nozzle lift mechanism including a cam follower device and a ratchet member generally similar to elements of the mechanism of the present invention.
None of the prior art patents and patent application listed above discloses an improved front wheel height adjuster for varying the height of the nozzle opening relative to the surface being cleaned and having an integral thumb wheel, lifting cam and locking ratchet unitary member together with associated parts all as claimed in the appended claims.